Question: $ { \left[\begin{array}{rr}{-2} & {-1} \\ {4} & {1}\end{array}\right]-\left[\begin{array}{rr}{2} & {1} \\ {2} & {-1}\end{array}\right] = {?} } $
To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{-2}-{2} & {-1}-{1} \\ {4}-{2} & {1}-{-1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{-4} & {-2} \\ {2} & {2}\end{array}\right]}$